ST. PAUL, Minn. (AP) — Twin Cities environmentalists have joined a campaign asking a food processing company to relocate its Arkansas hog farm.

Nearly 850 Minnesota residents have sent letters to Cargill expressing concern about the Mount Judea facility's proximity to the Buffalo River, Minnesota Public Radio News reported. The farm is located on a tributary six miles away from the river.

Jack Stewart, vice president of the Buffalo River Watershed Alliance in Arkansas, said the river's clear waters are surrounded by magnificent cliffs. Conservationists are concerned that manure runoff could taint the river.

Mike Martin, a Cargill spokesman, said neither the company nor the three Arkansas families who own the farm have done anything wrong.

"The concern is about a what-if scenario that may never take place, and the engineering on this farm goes well beyond anything that's required for environmental safeguards either by the federal government or the state of Arkansas," he said.

Martin said Cargill is listening to the concerns but has no plans to move. He said the company may consider adding more safeguards.

The Mount Judea hog farm is the largest in Arkansas. It houses 2,500 sows and nearly 4,000 piglets, all of which are owned by Cargill.

Stewart said there are other places in Arkansas that would welcome the Minnesota-based company and its operation.

"You know the people of Mt. Judea, about all they have, really, is an abundance of clean water and beautiful scenery," he said. "We don't think that, since it's a national river, that Arkansans should have to fight this battle alone. We need to band together when our national treasures are threatened."

"We've got an agricultural heritage as a state so we understand things like runoff and pollution and the impact it can have, and we know that we can do better," he said. "We value the companies that we have the most pride in, like Cargill, and we want them to continue to live up to the pride we invest in them."